i tried to solve it by myself but

in my expression as you see i get a totally different expression when i do coefficient of exponent then the one in the solution

did i do it correctly

$\displaystyle [CR_1+C\alpha \beta R_2]\frac{-\beta }{\tau }e^\frac{-t }{\tau }+Be^\frac{-t }{\tau }=V_0e^\frac{-t }{\tau }$

the alpha and beta dissapeared

why?